Recently, the concentration of nitrous oxide (NO) has been studied. because N2O is a greenhouse gas whose effect per molecule is more significant than that of carbon dioxide (CO), and also like chlorofluorocarbons (CFCs) and other ozone-destroying chemical elements it can cause ozone laver depletion. From 1996, the continuous monitoring of N2O has been done by gas-chromatography with an electron capture detector at our institute at Nagoya University (RAN) in Japan. Data of N2O were analyzed together with monitoring data of CO2 and methane (CH4) at the same university, by applying power spectral density, auto-correlation and cross-correlation techniques. As a result, weak correlations between N2O and CO2 or CH4 were found though their origins are thought to be different. This suggests that they are affected by the same phenomena at least partially. Moreover. correlations with the meteorological elements probably associated with the NO data are investigated. We will discuss the origins of N2O in a suburb of Nagoya on the basis of temporal variations and correlations with various elements. (C) 2004 Elsevier Ltd. All rights reserved.